Finding the distance between objects

Hi guys, sorry I know this has been asked before, I've been following the advice on the other posts but it's just not working and I can't figure out why.

I'm trying to find the distance between the current object and the player, I've assigned "PlayerTag" in the tags section to my player object and I'm trying to get the distance between the two and output it to the console. Here's my code:

 using UnityEngine;
 using System.Collections;
 
 public class EnemyController : MonoBehaviour {
     
     public float hitpoints = 100f;
     //Get player object
     GameObject player;
 
     float distance;
 
     void awake()
     {
         player = GameObject.FindGameObjectWithTag("PlayerTag");
     }
 
     void update()
     {
         //get distance between player and zombie
         distance = Vector3.Distance (gameObject.transform.position, player.transform.position);
         //output distance to console [DEBUG]
         Debug.Log ("Distance: " + distance);
     }
     
     public void RecieveDamage(float amt) 
     {
         hitpoints -= amt;
         if (hitpoints <= 0) 
         {
             Die();
         }
     }
     
     void Die() 
     {
         Destroy (gameObject);
     }
 }
 

can you guys spot what's wrong? I'm sure it's something dumb but I've been looking at it for a while now and I just don't see it.